Finding the Dino Killer

by Paul Gilster on October 23, 2007

By Larry Klaes

Tau Zero journalist Larry Klaes now returns with a look at the impact that evidently killed the dinosaurs, and the unusual family of planetoids now thought responsible. Is Chicxulub an event that could only have happened in the distant past, or a warning of possible danger ahead?

About 65 million years ago, a large planetoid at least six miles in diameter struck our planet at what is now the Yucatan Peninsula in Mexico, leaving a crater over 100 miles across. The force of the impact, which was two million times more powerful than the greatest nuclear bomb ever detonated, instantly killed every living thing within a one thousand mile radius.

Many other creatures suffered similar fates when debris from the planetoid impact flung high into the air came plunging back to the ground, setting off firestorms that spread across the globe. The clouds of smoke and dust from this event hung in our atmosphere for several years, blocking out the Sun and terminating many plants that relied on solar energy for photosynthesis. As a result, many plant eating creatures died from the loss of their food source, which in turn affected the animals that preyed on them.

The dinosaurs, having existed on Earth for over 160 million years, were among those victims who disappeared from our planet. The mammals, which until then had been little more than groups of rodents, came to prominence and are among the dominant species today, with humanity being among their members.

One major factor that remained unknown was what made what is now called the Chicxulub crater. Scientists assumed it was either a planetoid or comet, but the ‘Dino Killer’s’ exact nature and place of origin seemed lost in time and space.

Now a team of team of researchers from the Southwest Research Institute (SwRI) and Charles University in Prague think they may know where the space rock in question came from. They have described their ideas in an article titled, “An asteroid breakup 160 Myr ago as the probable source of the K/T impactor,” published in the September 6 issue of the science periodical Nature.

According to the theory developed by the international team, which includes Dr. William Bottke (SwRI), Dr. David Vokrouhlicky (Charles University, Prague), and Dr. David Nesvorny (SwRI), about 160 million years ago – give or take 20 million years – a large planetoid residing deep within the planetoid belt between the planets Mars and Jupiter was struck by a smaller but still significantly sized planetoid. The resulting debris became what is known today as the Baptistina planetoid family.

Some of the many pieces from this family eventually drifted from the planetoid belt and became Earth-crossing objects. One space rock from the Baptistina family may have struck our Moon some 108 million years ago, creating the prominent ray crater Tycho in the lunar southern hemisphere. Another family member went on to form our planet’s Chicxulub crater, significantly changing the types of creatures on Earth 65 million years ago.

Support for these conclusions comes from the impact history of Earth and Moon. Both worlds bear the scars of a two-fold increase in the formation rate of large craters over the last 100 to 150 million years.

“The Baptistina bombardment produced a prolonged surge in the impact flux that peaked roughly 100 million years ago,” explained Nesvorny. “This matches up pretty well with what is known about the impact record.”

For those who might think that the threat to our world from space has passed, Bottke warns that “…we are in the tail end of this shower now. Our simulations suggest that about 20 percent of the present-day, near-Earth asteroid population can be traced back to the Baptistina family.” This means there is still a chance that a Near Earth Object (NEO) could strike our planet, causing destruction and death on a level equivalent to the one experienced by the dinosaurs.

Ever since humanity became aware of this celestial danger, some scientists and others have been devising means to keep our species from going the way of the dinosaurs. As they planned methods to deflect and destroy NEOs that could strike Earth, they also realized that a detailed knowledge about the types of bodies that threaten our world needed to be made. Otherwise, an incorrect technique to protect our planet could make a bad situation worse.

One method scientists have deployed to learn more about NEOs is with powerful radar beams from Earth, which determine not only the shape of such planetoids but also their makeup. Radar helps researchers learn if a planetoid is a solid or porous body. Such information is critical when determining how best to deflect or destroy a space rock headed for our world.

The best tool for this task has been the Arecibo Radio Observatory on the island of Puerto Rico. The 1,000 foot wide dish is 25 times better than any other existing similar instrument for peering into the nature of these potentially deadly objects in space.

Unfortunately for this branch of science, budget constraints imposed upon Arecibo by the National Science Foundation (NSF) have curtailed much of the planetary radar operations from that facility. The very existence of Arecibo itself is in jeopardy through the year 2011. With no other comparable facilities being built for at least a decade or more, it is hoped that those who control the finances in these areas will see the wisdom in continuing the study and search for planetoids that could cause irreversible harm to our civilization and all life on Earth.

When Elon Musk has made a few more billion it might be a worthwhile investment for SpaceX.

One of the best defenses against asteroids IMHO would be the “Comet Chaser” solar-sail design of Gordon Dick and Duncan Lunan – uses a curved reflector sail which concentrates the light to a focus onto a smaller steerable mirror to create a beam to vapourise the target’s regolith. None of the smash-and-bash of kinetic asteroid deflectors and stand-off nukes – both of which would probably produce debris clouds that would impede other incoming impactors.

Extinction of the Dinosaurs – New Research May Have Solved One of the World’s Biggest Mysteries

Apparently, even killing dinosaurs was a job outsourced to India.
New research suggests that a series of monumental volcanic
eruptions in India may have killed off the dinosaurs 65 million
years ago.

Previously it was believed that the likely suspect was a meteor
impact in the Gulf of Mexico. However, the volcanic eruptions in
India, which created the gigantic Deccan Traps lava beds, are
now the prime suspect in the most famous and persistent
paleontological murder mystery. Scientists have…

The universal human myth may be the first example of disaster reporting.

by Scott Carney

The Fenambosy chevrons at the tip of Madagascar. Image courtesy of Dallas Abbott
The serpent’s tails coil together menacingly. A horn juts sharply from its head. The creature looks as if it might be swimming through a sea of stars. Or is it making its way up a sheer basalt cliff? For Bruce Masse, an environmental archaeologist at Los Alamos National Laboratory, there is no confusion as he looks at this ancient petroglyph, scratched into a rock by a Native American shaman. “You can’t tell me that isn’t a comet,” he says.

The plains of solidified lava that give the Moon its quirky human-like face as seen from Earth were created more than four billion years ago, according to a paper appearing on Thursday in Nature, the British science weekly.

The evidence comes from an unearthly silvery-grey stone that was blasted off from the face of the Moon, perhaps by an impacting asteroid, and was then captured by Earth’s gravity, prompting it to fall to ground in Botswana.

In 1999, the 13.5-kilo (29.7-pound) remnant of this roving rock was found by local people near the village of Kuke, in the grasslands of the Kalahari Nature Reserve, who then sold it to meteorite hunters.

The lunar heritage of the rock, named Kalahari 009, has been confirmed by a telltale signature of oxygen isotopes and ratio of iron to manganese in two volcanic minerals, olivine and pyroxene.

The nature of these chemicals puts the rock into the category of a mare basalt — a lava that flowed out smoothly onto the lunar surface before solidifying, forming dark plains that early skywatchers mistakenly took for seas, “Mare” in Latin.

A new analysis of fragments of phosphate in Kalahari 009 puts the rocks at the whopping old age of 4.35 billion years, give or take 150 million years, the Nature study says.

This implies that mare-type volcanism must have occurred at least as early as this date, just after the first stage of lunar crust formation, say the authors, led by Kentaro Terada of Hiroshima University in Japan and Mahesh Anand of Britain’s Open University.

Mare volcanism overlapped with a later stage of volcanism, evidence of which was found in rocks picked up by the Apollo missions.

The “Man in the Moon” comprises eyes made of the Mare Imbrium and Mare Serenitatis, a nose consisting of Sinus Aestuum, while the Mare Nubium and Mare Cognitum provide its mouth.

These and other mare account for nearly a sixth of the lunar surface, mostly on the side visible from Earth.

The Chicxulub Crater is an ancient impact crater buried underneath the
YucatÃ¡n Peninsula, with its center located near the town of Chicxulub,
YucatÃ¡n, Mexico. The crater is over 180 kilometers (110 mi) in
diameter, making the feature one of the largest confirmed impact
structures in the world; the asteroid or comet whose impact formed the
crater was at least 10 km (6 mi) in diameter. The crater was named for
the nearby town, as well as for the literal Maya translation of the
name: “tail of the devil.” The crater was discovered by Glen Penfield,
a geophysicist who had been working in the YucatÃ¡n while looking for
oil during the late 1970s. The presence of tektites, shocked quartz
and gravity anomalies, as well as the age of the rocks and isotope
analysis, show that this impact structure dates from the late
Cretaceous Period, roughly 65 million years ago. The impact associated
with the crater is implicated in causing the extinction of the
dinosaurs as suggested by the Kâ€“T boundary, although some critics
disagree that the impact was the sole reason and also debate whether
there was a single impact or whether the Chicxulub impactor was one of
several that may have struck the Earth at around the same time. Recent
evidence suggests that the impactor was a piece of a much larger
asteroid which broke up in a collision more than 160 million years
ago.

The most detailed three-dimensional seismic images yet of the Chicxulub crater, a mostly submerged and buried impact crater on the Mexico coast, may modify a theory explaining the extinction of 70 percent of life on Earth 65 million years ago. The Chicxulub crater was formed when an asteroid struck on the coast of the Yucatan Peninsula. Most scientists agree the impact played a major role in the “KT Extinction Event” that caused the extinction of most life on Earth, including the dinosaurs.

According to Sean Gulick, a research scientist at the Institute for Geophysics at The University of Texas at Austin’s Jackson School of Geosciences and principal investigator for the project, the new images reveal the asteroid landed in deeper water than previously assumed and therefore released about 6.5 times more water vapor into the atmosphere.

By refining a technique used to date rocks and fossils,
scientists have now determined the date of the dinosaurs’
extinction with pinpoint accuracy. The finding sheds new
light on one of the most dramatic periods in the evolution
of life on Earth.

The moon’s “near side” always faces Earth, because the moon spins once on its axis in precisely the same amount of time it takes to revolve around the Earth. But things could have been different billions of years ago. A computer analysis of the amount of craters on the different hemispheres of the Moon shows that the far side may have once been facing Earth. A large asteroid impact may caused the moon to change the way its faces Earth.

One consequence of the Moon being locked in a spin-orbit resonance of synchronous rotation is that more impacts should occur on the Moon’s western hemisphere than the eastern, as that side would be facing into orbit, making it more likely to be hit by debris.

But Mark Wieczorek and Matthieu Le Feuvre at the Paris Institute of Earth Physics in France compared the relative ages of the craters, using data about the sequence in which ejected material was deposited on the surface, and they found the opposite to be true. Although the youngest impact basins were concentrated in the western hemisphere, as expected, the older craters were mostly congregated in the east. This suggests that the eastern face had once been bombarded more than the western face.

This could have happened if a large asteroid impact caused the moon to do an about face. The researchers estimate after the impact, the moon would have appeared to turn slowly as viewed from Earth, and slowly would have come into its current position.

In looking at several of the largest lunar impact basins, there are several suspects for impacts that could have temporarily unlocked the Moon from synchronous rotation.

Charter

In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For the last nine years, this site has coordinated its efforts with the Tau Zero Foundation, and now serves as the Foundation's news forum. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image: Marco Lorenzi).

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